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Fixing System
Overview
The fixing power supply controls temperatures of the Fixing Assembly.
This product employs the on-demand fixing method in the Fixing Assembly. The figure below shows the structure schematically.
DC Controller
Fixing Heater
Safety Circuit
Fixing Power Supply
Fixing Control
Circuit
TH802
TH801
TH803
FU1
H100
Fixing Temperature Signal
Fixing Heater
Drive Signal
Fixing Film
Pressure Roller
Name
Symbol
Role
Fixing heater
100V
H100
To heat the fixing film
120V
H120
230V
H220
Main thermistor
TH801
To detect the fixing heater temperature (center of the heater, contact ther-
mistor)
Sub thermistor 1
TH802
To detect the fixing heater temperature (heater ends, contact thermistor)
Sub thermistor 2
TH803
Temperature fuse
FU1
To prevent abnormal temperature rise in the fixing heater
The temperature fuse is attached to the center of the fixing heater.
When the fixing heater comes to be abnormally hot, the temperature fuse is open to shut off the power supply to the fixing heater.
The thermistor detects the fixing heater temperature to input the temperature detection signal to the DC controller. Note that
temperatures at heater ends are not detected in models of MF8200 series with slower print speed.
The temperatures in the whole fixing assembly are controlled by the fixing control circuit and the fixing heater safety circuit based
on commands from the DC controller.
Controls
■ Fixing Speed Control
● Reduction of Throughput Based on Detected Temperature of Sub Thermistor
Paper interval extension time is determined based on the detected temperature of the Sub Thermistor.
Paper interval extension time determined by the detected temperature of the Sub Thermistor is added to the paper interval
extension time derived from the paper width detection result and paper length detection result.
Detection of temperature by the Sub Thermistor is performed when the Delivery Sensor turns OFF.
When the Paper Width Sensor is ON, reduction of throughput based on the detected temperature of the Sub Thermistor is not
executed.
Tempreture of Sub Thermistor: Tx
Paper interval (sec)
T1
3
T2
6
T3
9
T4
15
2. Technical Explanation
41
Summary of Contents for MF724Cdw
Page 1: ...Revision 2 0 MF720 Series Service Manual ...
Page 12: ...Product Overview 1 Product Lineups 5 Product Features 7 Specifications 8 Name of Parts 14 ...
Page 79: ...4 Click Import Export Import 1 2 2 Technical Explanation 71 ...
Page 103: ...Durable Parts No durable parts is set for this product 3 Periodical Service 95 ...
Page 104: ...Periodical Services No periodical service is set for this product 3 Periodical Service 96 ...
Page 232: ...Adjustment 5 Overview 225 Adjustment at Parts Replacement 226 ...
Page 248: ...Troubleshooting 6 Test Print 241 Trouble shooting items 243 Version Upgrade 244 Debug Log 248 ...
Page 258: ...Error Jam Alarm 7 Outline 251 Error Codes 252 Jam Code 257 ...
Page 267: ...Service Mode 8 Overview 260 COPIER 264 FEEDER 300 FAX 302 TESTMODE 308 ...
Page 322: ...APPENDICES Service Tools 315 General Circuit Diagram 316 Print Sequence 317 Backup Data 318 ...